3D camera module

ABSTRACT

A 3D depth camera module, including a light transmitting portion having a laser for emitting light, and having a diffractive optical element for passing the light therethrough such that the light reaches a subject with a preset pattern; a light receiving portion configured to receive the light reflected from the subject; an analyzing portion configured to analyze a 3D shape of the subject, based on a shifted degree of the reflected light; and an operating portion configured to move part of the light transmitting portion such that a position of one region of the subject where the light reaches is changed. Further, the operating portion moves at least part of the light transmitting portion by a predetermined length being set to restrict repetitive arrival of the light onto one region of the subject; the diffractive optical element includes a plurality of spots spaced from each other by a predetermined spaced interval between two adjacent spots of the diffractive optical element; and the predetermined length is smaller than the predetermined interval.

TECHNICAL FIELD

The present invention relates to a 3D camera module capable ofprocessing a shape in the form of an image by recognizing a depth of anobject.

BACKGROUND ART

The conventional camera obtains depth information, three-dimensional(3D) information, based on an image obtained by using a two-dimensional(2D) image sensor. Recently, a structured light method and a time offlight (TOF) method are used. The structured light method is used tomeasure a depth of an object by irradiating laser light on which aspecific pattern has been coded onto the object, and by calculating apattern shift amount of the reflected light. And the TOF method is usedto measure a depth of an object by directly irradiating light onto theobject, and by calculating time taken for the reflected light to return.

However, the structured light method has a restriction in miniaturizingthe 3D camera module due to a physical size of a light transmittingportion and a light receiving portion configured to receive reflectedlight and using a laser optical source. This may cause a difficulty inapplying the structured light method to mobile products. Further, thestructured light method adopts a fixed focal lens and a passive codingdevice. This may cause the structured light method not to have aflexible scheme to enhance a depth resolution.

Next, the TOF method has a limitation in usage, due to a high cost of aToF exclusive sensor which calculates a time proportional to a distanceof return light, and high power consumption of an LED having itsbrightness modulated. Recently, a 3D camera is being presented toenhance a performance through an image synthesis with the conventional2D camera. For instance, an RGBIR camera for measuring a 2D image and a3D depth by a single camera is being developed. The RGBIR camera isimplemented by combining a 2D camera and a 3D IR camera for depthmeasuring, and uses an RGBIR sensor and a single lens.

However, in the RGBIR camera, RGB light is incident onto IR pixels ascrosstalk, and IR light is incident onto RGB pixels as crosstalk. Thismay cause optical noise, and thus lower performance.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a 3D camerahaving an enhanced resolution.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein,there is provided a 3D camera module, including: a light transmittingportion having a laser for emitting light, and having a diffractiveoptical element for passing the light therethrough such that the lightreaches a subject with a preset pattern; a light receiving portionconfigured to receive the light reflected from the subject; an analyzingportion configured to analyze a 3D shape of the subject, based on ashifted degree of the reflected light; and an operating portionconfigured to move part of the light transmitting portion such that aposition of one region of the subject where the light reaches ischanged.

In an embodiment of the present invention, the operating portion may beformed to transfer an entire part of the light transmitting portion.

In an embodiment of the present invention, the light transmittingportion may further include: a lens portion configured to change thelight into parallel light; and a mirror portion configured to reflectthe parallel light which has passed through the lens portion, to thediffractive optical element. And the operating portion may be connectedto the mirror portion to change a reflection direction of the light.

In an embodiment of the present invention, the mirror portion mayinclude a plurality of digital micro-mirror devices (DMDs), and theoperating portion may move at least one of the DMDs.

In an embodiment of the present invention, the operating portion may beformed to move the diffractive optical element.

In an embodiment of the present invention, the operating portion maymove at least part of the light transmitting portion by a predeterminedlength, and the predetermined length may be set to restrict repetitivearrival of the light onto one region of the subject.

In an embodiment of the present invention, the diffractive opticalelement may include a plurality of spots spaced from each other by apredetermined interval, and the predetermined length may be formed to besmaller than the predetermined interval.

In an embodiment of the present invention, the 3D depth camera modulemay further include a camera sensor configured to record the lightreflected from the subject, based on a preset input signal. And anoperation signal to activate the operating portion in order to move atleast part of the light transmitting portion may be output in asynchronized manner with the input signal.

In an embodiment of the present invention, the camera sensor may includean image processing portion configured to form a color image using thelight.

Firstly, the operating portion of the present invention may beconfigured to move at least one component of the light transmittingportion such that light may reach different regions of the subject asmuch as possible.

With such a configuration, a resolution may be enhanced without increaseof the number of spots where light passes. This may allow a shape of thesubject to be predicted more accurately, and may allow the shape to beoutput in the form of an image of enhanced quality.

The camera module may recognize a depth of a small object moreprecisely, and may provide a partial shape of the single subject in moredetail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating appearance of a depth cameraaccording to an embodiment of the present invention;

FIG. 2A is a conceptual view for explaining a light transmitting portionand a light receiving portion of a depth camera according to the presentinvention;

FIG. 2B is a conceptual view for explaining a diffractive opticalelement included in a light transmitting portion;

FIGS. 3A and 3B are conceptual views of a light transmitting portionformed such that at least one component thereof is moveable; and

FIGS. 4A to 4E are conceptual view for explaining a resolution increasedue to a movement of a diffractive optical element.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Description will now be given in detail according to exemplaryembodiments disclosed herein, with reference to the accompanyingdrawings. For the sake of brief description with reference to thedrawings, the same or equivalent components may be provided with thesame or similar reference numbers, and description thereof will not berepeated. In general, a suffix such as “module” and “unit” may be usedto refer to elements or components. Use of such a suffix herein ismerely intended to facilitate description of the specification, and thesuffix itself is not intended to give any special meaning or function.In the present disclosure, that which is well-known to one of ordinaryskill in the relevant art has generally been omitted for the sake ofbrevity. The accompanying drawings are used to help easily understandvarious technical features and it should be understood that theembodiments presented herein are not limited by the accompanyingdrawings.

FIG. 1 is a perspective view illustrating appearance of a depth cameraaccording to an embodiment of the present invention. FIG. 2A is aconceptual view for explaining a light transmitting portion and a lightreceiving portion of the depth camera according to the presentinvention. And FIG. 2B is a conceptual view for explaining a diffractiveoptical element included in the light transmitting portion.

The depth camera 1000 according to the present invention includes alight transmitting portion 100 configured to emit light to a subject 0,a light receiving portion 500 configured to receive the light reflectedfrom the subject 0, and an analyzing portion (not shown) configured toanalyze a 3D shape of the subject using the light collected by the lightreceiving portion 500. The depth camera 1000 of the present inventionirradiates light from the light transmitting portion 500 to the subject0, and calculates a shift amount of the light reflected from the subject0, thereby analyzing a depth of a partial region of the subject 0. Thatis, the light transmitting portion 100 and the light receiving portion500 are spaced from each other by a predetermined distance.

The light transmitting portion 100 includes a laser 110 configured toemit light as an optical source, and a lens portion 120 configured toconvert the light generated from the laser 110 into parallel light. Thelens portion 120 may be configured as a collimator lens.

The light transmitting portion 100 includes a diffractive opticalelement 130 configured to transform the parallel light by the lensportion 120, into light having a preset resolution.

FIG. 2B is a conceptual view illustrating a diffractive optical element130 in an enlarged manner. Circular regions mean regions (spots) wherediffracted light passes through. The diffractive optical element 130 isformed to have a predetermined number of spots. For instance, thediffractive optical element 130 may include about 50,000 spots. This maycorrespond to about 4% of an entire area of the diffractive opticalelement 130.

Light which has passed through the diffractive optical element 130reaches the subject 0, with a preset resolution. That is, a depth of thesubject 0 is determined based on the number of spots included in thediffractive optical element 130. Accuracy in recognizing a depth of thesubject 0 is reduced when a size of a spot formed in the diffractiveoptical element 130 of the same size is small, and when a distance tothe subject 0 is long.

The light receiving portion 500 includes at least one lens 510, and animage processing portion 520 including an RGB filter. A color imageusing the light which has reached the subject 0 may be generated by theimage processing portion 520.

In the present invention, a region of the subject where light reaches isincreased as at least one component of the light transmitting portion100 is moved. That is, the light transmitting portion 100 is formed suchthat light which has passed through the diffractive optical element 130reaches different regions.

FIGS. 3A and 3B are conceptual views of a light transmitting portionformed such that at least one component thereof is moveable. Referringto FIG. 3A, the light transmitting portion 100 includes an operatingportion 300 configured to move at least one component of the lightemitting portion 100.

A direction to move at least one component of the light emitting portion100 by the operating portion 300 is perpendicular to a direction to emitlight from the laser 110. For instance, if the laser 110 irradiateslight to a front side toward the subject 0, the operating portion 300may move the at least one component in at least one direction amongupper and lower directions, right and left directions, and a diagonaldirection.

The operating portion 300 may be formed to move the light transmittingportion 100 wholly. For instance, the light transmitting portion 100 maybe formed as a single light emitting module, the operating portion 300may be formed at the light emitting module, and the light emittingmodule may be moved on the basis of the light receiving portion 500.

The operating portion 300 is synchronized with the image processingportion 520 in order to move the at least one component. That is, anoperation to move a component by the operating portion 300, and a signalto input light by the light receiving portion 500 are synchronized witheach other.

Once the light transmitting portion 100 moves by the operating portion300, a region on the subject 0 where light emitted from the lighttransmitting portion 100 reaches is also changed. Accordingly, the lightmay be reflected from a larger number of regions, and may be made to beincident onto the light receiving portion 500. That is, a resolution ofthe light to determine a depth of the subject 0 is increased.

Although not shown, the operating portion 300 may move the lighttransmitting portion 100 at preset time intervals. Alternatively, theoperating portion 300 may be controlled to move the light transmittingportion 100 at preset time intervals.

For instance, the preset time interval is preferably formed to besmaller than a distance between the spots. This may prevent light fromrepeatedly reaching one region of the subject where the light hasreached, and thereby may enhance a resolution.

The operating portion 300 may move at least one of the diffractiveoptical element 130 and the laser 110, according to a preset basis. Oncethe diffractive optical element 130 moves, light is distributed to haveanother pattern. This may cause a region of the subject 0 where lightreaches, to be changed. Further, if the laser 110 (optical source)moves, light reaches another region of the diffractive optical element130. This may provide the same effect as an operation to move thediffractive optical element 130.

A light transmitting portion 101 shown in FIG. 3B may include a mirrorportion 140 configured to change a moving path of light. The mirrorportion 140 is disposed on a moving path of light, and reflects thelight such that the light reaches the diffractive optical element 130.The mirror portion 140 may include a plurality of digital micro-mirrordevices (DMD).

The operating portion 300 may be mounted to the mirror portion 140 tomove the mirror portion 140. For instance, the operating portion 300 mayconvert a reflection direction of the light by controlling an angle ofthe mirror portion 140.

Although not shown, if the camera module includes a prism, the operatingportion 300 may rotate or move the prism.

The operating portion 300 may be mounted to at least one of theplurality of DMDs.

The operating portion 300 may be mounted to a plurality of components tochange a moving path of the light. Accordingly, the number ofdistinguishable regions of the subject where the light reaches isincreased, and a resolution of the light to detect a depth of thesubject is increased.

Hereinafter, a moving path of the diffractive optical element 130 willbe explained with reference to the attached drawings.

FIGS. 4A to 4E are conceptual view for explaining a resolution increasedue to a movement of a diffractive optical element.

Although not shown, the light transmitting portion, the light receivingportion, and FIG. 4A correspond to a case where the diffractive opticalelement is not moved. Bright regions mean regions where parallel lightemitted from the laser pass through in a distributed manner to reach thesubject. That is, the distributed light reaches the separated regions ofthe subject 0.

For instance, light does not reach regions ‘A’ and ‘B’ of the subject 0.This may cause light reflected from the regions ‘A’ and ‘B’ not to bereceived, and the regions ‘A’ and ‘B’ not to be recognizable.

FIG. 4B illustrates a case where the diffractive optical element 130 hasmoved upward based on the laser 110. As the diffractive optical element130 moves, parallel light emitted from the laser 110 may reach anotherregion of the subject 0.

For instance, light may reach the region ‘A’ of the subject 0, and maynot reach the region ‘B’ of the subject 0. As a result, the lightreceiving portion may receive the light reflected from the region ‘A’,and may detect a depth and a shape of the region ‘A’ by analyzing ashift of the light.

As a region on the subject 0 where lightreaches is changed, theanalyzing portion (not shown) may compare a shape of the subject 0derived from the case of FIG. 4A, with a shape of the subject 0 derivedfrom the case of FIG. 4B. Then, the analyzing portion may calculate adepth of each region on the subject, and may analyze a shape of thesubject 0.

FIG. 4C illustrates a case where the diffractive optical element 130 hasmoved downward from the state shown in FIG. 4A. FIG. 4C illustrates thatlight does not reach the regions ‘A’ and ‘B’. In this case, it isimpossible to analyze a shape of the subject 0 at the regions ‘A’ and‘B’. However, the analyzing portion (not shown) predicts a shape of thesubject 0 at the regions ‘A’ and ‘B’, based on light which has reachedanother region of the subject 0.

FIG. 4D illustrates a case where the diffractive optical element 130 hasmoved rightward from the state shown in FIG. 4A. In this case, light mayreach the regions ‘A’ and ‘B’, and the light receiving portion 500 mayreceive the light reflected from the regions ‘A’ and ‘B’. And theanalyzing portion may calculate a depth of the subject 0 at the regions‘A’ and ‘B’, and may predict a shape of the subject 0 at the regions ‘A’and ‘B’.

FIG. 4E illustrates a case where the diffractive optical element 130 hasmoved leftward from the state shown in FIG. 4A. In this case, like inFIG. 4C, light does not reach the regions ‘A’ and ‘B’.

The operating portion may move at least one component of the lighttransmitting portion such that light may reach different regions on thesubject as much as possible.

With such a configuration, a resolution may be enhanced without increaseof the number of spots where light passes. This may allow a shape of anobject to be predicted more accurately, and may allow the shape to beoutput in the form of an image of enhanced quality.

The camera module 1000 may recognize a depth of a small subject moreprecisely, and may provide a partial shape of the single subject in moredetail.

The 3D depth camera module is not limited to the configuration and themethod of the aforementioned embodiments. Rather, the embodiments may beselectively combined to each other partially or wholly, for variousmodifications.

The present invention may be applicable to various industry fields usinga 3D camera which recognizes a shape of an object and provides a 3Dimage.

The invention claimed is:
 1. A 3D depth camera module, comprising: alight transmitting portion having a laser for emitting light, and havinga diffractive optical element for passing the light therethrough suchthat the light reaches a subject with a preset pattern; a lightreceiving portion configured to receive the light reflected from thesubject; an analyzing portion configured to analyze a 3D shape of thesubject, based on a shifted degree of the reflected light; and anoperating portion configured to move part of the light transmittingportion such that a position of one region of the subject where thelight reaches is changed, wherein the operating portion moves at leastpart of the light transmitting portion by a predetermined length beingset to restrict repetitive arrival of the light onto one region of thesubject, wherein the diffractive optical element includes a plurality ofspots spaced from each other by a predetermined spaced interval betweentwo adjacent spots of the diffractive optical element, and wherein thepredetermined length is smaller than the predetermined interval.
 2. The3D depth camera module of claim 1, wherein the operating portiontransfers an entire part of the light transmitting portion.
 3. The 3Ddepth camera module of claim 1, wherein the light transmitting portionfurther includes: a lens portion configured to change the light intoparallel light; and a mirror portion configured to reflect the parallellight which has passed through the lens portion, to the diffractiveoptical element, and wherein the operating portion is connected to themirror portion to change a reflection direction of the light.
 4. The 3Ddepth camera module of claim 3, wherein the mirror portion includes aplurality of digital micro-mirror devices (DMDs), and wherein theoperating portion moves at least one of the DMDs.
 5. The 3D depth cameramodule of claim 1, wherein the operating portion is formed to move thediffractive optical element.
 6. The 3D depth camera module of claim 1,further comprising a camera sensor configured to record the lightreflected from the subject, based on a preset input signal, wherein anoperation signal to activate the operating portion in order to move theat least part of the light transmitting portion is output in asynchronized manner with the input signal.
 7. The 3D depth camera moduleof claim 1, wherein the camera sensor includes an image processingportion configured to form a color image using the light.